1. Field of the Invention
This invention relates to the container body for agricultural mixers, specifically vertical type feed mixers.
2. Background of the Invention
Agricultural mixers are used for mixing feed materials such as hay, silage and other nutrients including animal feed supplements and grains. These feed materials are then discharged and fed to various livestock such as cattle and dairy cows. Sometimes the mixing of such feed includes depositing a whole round or square bale of hay into the mixer. The mixer then cuts and processes the bale into the desired consistency before and during the mixing of the other feed nutrients.
In known mixers, there are many different configurations including horizontal augers, reel type arrangements, and vertical augers. In the vertical auger type mixers, the auger and container body designs are generally similar. The auger design generally includes a center core on a vertical axis, with helical auger flighting wrapped around this core. The auger flighting has an overall conical appearance, being wider at the base and narrower at the top. The flighting can also include individual paddles or segmented flighting sections oriented in a helical pattern to urge the material in the desired direction. Knives are added to the flighting to help cut and process the feed materials.
The container body designs include a horizontal floor, which closely approximates the diameter of the vertical auger at its base. Walls extend upward from the floor to form a container with an open top, so that feed materials can be loaded from above.
The walls of the container are in the shape of an inverted frustum, being wider at the top and narrower at the base. However, the walls on the sides of the container are typically arranged at a steeper angle in comparison to the walls on the ends of the container. The resulting container shape is that of a flexible plastic bowl with a flat bottom, being squeezed in at the top edge along two opposing sides. The reasons for this shape in vertical mixers is both to narrow the overall profile of the container, and to facilitate feed processing inside the mixer. A similar shape is utilized in the case of multiple auger mixers, with the frustum shape being stretched to accommodate the additional augers.
The oblong shape of the vertical mixer container at the top edge, combined with the cone shape of the auger, creates a wide cavity for the reception of feed at the ends of the container, and a narrower cavity at the sides of the container. During the mixing of feed inside the container, the auger rotates at a constant speed, urging the feed materials around the inside circumference of the container. When the feed encounters the narrower cavities at the sides, a restriction point is created, thus forcing a mixing action as well as allowing the auger knives to further cut or process the feed materials. As the feed moves into the wider cavities at the ends of the container, the feed increases in velocity and falls down into the cavity. The resulting rotary motion of the feed is that of alternating restriction and release, slow and fast, rising and falling movement, which causes the mixing and processing of the materials.
A discharge opening is typically located at the lower edge of the container wall to discharge the feed materials after mixing. The most efficient location for discharging materials is at the ends of the container, where the cavities are larger and the feed flows better and thus discharges more freely. Once discharged at the end of the container, the feed must be moved to the side of the container where it is normally unloaded. This requires a long discharge chute to carry the feed materials from the front or rear of the container to the side of the container. An alternative is to have a discharge opening on the side of the container, but this restriction point typically has more pressure and binding of the feed, and is less desirable than a discharge opening on the ends of the container.
When a full load of feed is circulating inside the container, a common problem is spilling and feed retention. When the feed is restricted at the sides of the container, it tends to lift the feed and spill over the edges. Manufacturers have devised several methods of retaining the feed inside the container, including chains, pipes, plastic or other structural components, which must be attached at both sides of the container.
In vertical mixers in which the sides of the container are symmetrical, one disadvantage is that the feed is restricted in two places along the inside circumference of the container. This redundant action slows the mixing action twice per revolution.
Another disadvantage of symmetrical container sides with two restriction points is that it creates spilling of feed on both sides of the mixer, generally requiring two sets of feed retention devices to be installed.
Another disadvantage of symmetrical container sides is that additional horsepower is required for the auger knives to cut and process the feed materials on both restrictive sides of the container at the same time.
Another disadvantage of symmetrical container sides is that the discharge opening is placed on the container ends for the best discharging efficiency, requiring the use of a long conveyor to reach the sides of the machine for unloading.
Another disadvantage of symmetrical container sides is that the tongue and hitch is normally centered on the container. With the discharge chute extended to the side for unloading, the discharging feed extends a greater distance from the centerline of the towing vehicle. This forces the towing vehicle to travel off-center when discharging feed materials, and makes it more difficult for the operator to view the discharge progress during the unloading operation of the mixer.